It is assumed that such a method is generally known per se, but there is a possibility of employing it in connection with transport of oil by means of tankers, and more specifically during the loading thereof. In the case of such an application, which can be regarded as novel, however, the non-condensed fractions would be released directly into the open air from the first passage of the first heat exchanger. Since refrigerating energy has also been used for cooling of these fractions, the energy which has been employed for cooling these fractions is thereby lost.
Similarly, particularly in the case of the above-mentioned application, in order to provide the refrigerated coolant, a known per se cooling plant can be employed with a capacity which is adapted to the cooling capacity which has to be produced during the condensation. The plant therefore has to be relatively large and thus space consuming and expensive. Since the cooling plant is only used during the oil loading, for economic reasons it is stopped while the ship is underway. The short operating time of the cooling plant in relation to the long period during which it is not in operation is a contributing factor to its unsatisfactory utilization.